In the papermaking art, an aqueous suspension containing cellulosic fibres, and optional fillers and additives, referred to as stock, is fed into a headbox which ejects the stock onto a forming wire. Water is drained from the stock through the forming wire so that a wet web of paper is formed on the wire, the paper web is further dewatered in the press section, and dried in the drying section of the paper machine. Drainage and retention aids are conventionally introduced into the stock in order to facilitate drainage and to increase adsorption of fine particles onto the cellulosic fibres so that they are retained with the fibres on the wire.
U.S. Pat Nos. 4,750,974 and 4,643,801 discloses a coarcervate binder for use in a papermaking process. First cationic potato starch is added into the process, then an anionic mixture comprising anionic polymer and silica is added. The mixture contains 20:1 to 1:10 of anionic polymer to silica.
U.S. Pat. No. 6,083,997 discloses anionic nano-composites, which are prepared by adding a polyelectrolyte to silicate solution and then combining them with silicic acid. The nano-composites exhibit improved retention and drainage performance in papermaking processes.
U.S. Pat. No. 5,167,766 discloses a papermaking process in which an ionic organic polymer microbead is used together with a synthetic organic polymer or polysaccharide as retention and drainage aids.
It would be advantageous to be able to provide drainage and retention aids with improved performance. It would also be advantageous to be able to provide retention and drainage aids with good storage stability. It would further be advantageous to be able to provide a papermaking process with improved drainage and/or retention performance.